Seeking the Heath Tiger Beetle

As readers of this blog will know, I have been spending some time this year doing surveys on Dorset's Purbeck Heaths National Nature Reserve for the RSPB, ARC and the Purbeck Natural History Forum. Mostly these were reptile surveys, but I've also strayed into other taxa, such as the fascinating Purbeck Mason Wasps and Heath Tiger Beetles which are the subject of this post.

Heath Tiger Beetle Cicindela sylvatica - Wareham Forest, Dorset 2026

So - what are Heath Tiger Beetles and why are they of interest?

As a group, tiger beetles are agile and voracious hunters. Fast moving, with large eyes and larger jaws they move at speed in search of a range of small invertebrate prey. There are five species in Britain, only one of which is widespread and well-known - the Green Tiger Beetle (below). I've seen these in a range of habitats including lowland heath (such Arne in Dorset), bogs (the Shropshire meres) and upland grassland (Brecon Beacons) - but never in an intensively farmed area. Look for them in Britain's wild places (see NBN Atlas distribution map).

Green Tiger Beetle Cicindela campestris - Bovey Heath, Devon 2013

The Heath Tiger Beetle is one of the other four rarities. In Britain, it is exclusively a species of lowland heaths, with almost all records coming in a belt running from the east Dorset heathlands up to Surrey - see the NBN Atlas map. But do not be fooled by the satisfyingly large splodges on the large scale version of this map. If you drill down into the detail, you will see that even within apparently favoured habitats, the actual distribution of the species is patchy at best. 

What Heath Tiger Beetles seem to like are low-lying moorlands with a mosaic of different aged heather (Calluna and Erica) interspersed with open sandy areas. The photo below shows Heath Tiger Beetle habitat in Wareham Forest, Dorset. Bare ground is important for a number of reasons. Adults use it for hunting, and also to warm up out of the shade on cooler mornings. Sandy areas are also used by Heath Tiger Beetle larvae, which dig burrows before moulting (they probably undergo three moults) and eventually pupating. They can spend 1-3 years underground, emerging to hunt, while adults can live a further one or two years. Summer is the time of greatest adult activity, especially between May and July. 

Heath Tiger Beetle habitat - Wareham Forest, Dorset

Heath Tiger Beetle numbers have been in decline, in line with the loss and fragmentation of Britain's lowland heathlands. It is on the Red List of endangered species. The good news is that conservation action is already underway. General protection of heathland habitat from fire and encroachment by gorse, pine or (even worse) development is the obvious starting point, but more targeted action has been carried out with the creation of around 300 scrapes - strips of bare land several metres wide - at eight sites across Dorset's Purbeck Heaths and Wareham Forest. This has shown encouraging results, with an increase in recorded sightings. Ongoing monitoring is an important part of this process, which is where the Purbeck Natural History Forum surveys come in.

I was keen to get involved this summer, but came rather late to the party as I had no prior experience of the species. If you're doing a survey then you need to know what to look for. Advice from Howard Inns pointed me to a site in Wareham Forest, where I headed in mid-June to find my first Heath Tigers. Early omens were good, as I almost immediately came across a lovely female Sand Lizard watching me through the cover of a gorse bush next to the path (below). This was a nicely undisturbed place.

Sand Lizard - Wareham Forest, Dorset

Nevertheless, the Heath Tiger Beetles initially proved elusive. I spent about 15 minutes walking suitable trails without a beetle in sight, before reaching some of the scrapes mentioned above. And, as if on cue, the beetles appeared - at least 10 individuals.

Both Heath and Green Tiger Beetles have a distinctive pattern of behaviour that makes them easy to spot once you've got your eye in. (Or course you then need to check that you have the correct species, as both are present on the Dorset heathlands.) Look for a fast-moving beetle patrolling across the bare ground. As you approach, the beetle will almost certainly fly off, keeping low to the ground, landing a metre or so ahead. The trick is to note where it lands, approach slowly and then observe it with a pair of close-focussing binoculars - plus, in my case, a long camera lens:

Heath Tiger Beetle - Wareham Forest, Dorset 2026

The beetles are more easily seen against light-coloured sandy soil. In the deep heather they would be almost impossible to spot, which raises the question of whether they occur more widely across the heathland but are only recorded from bare ground because this is where we can see them, The jury may still be out on that one.
 

The rest of the tale is one of anticlimax, I'm afraid. After my Wareham Forest initiation I went on to survey Scotland Heath (one of the Purbeck Heaths) for Heath Tiger Beetles, but found none. Given the relative lack of bare ground on that site, this wasn't a huge surprise, although I did come across some Purbeck Mason Wasps which was a bonus. Later on in the season I also walked over a known site for Heath Tiger Beetles on Purbeck (Slepe Heath), but only managed a single sighting - and that one escaped into the heather before I could get a photo. It was however on an incredibly hot July afternoon, so possibly not the best time for carrying out a survey.  

But at least I'll be ready for next year.

Afterword

A couple of additional points for the sake of completeness.

There is some confusion about the Heath Tiger Beetle's common name. Some publications refer to it as Wood Tiger Beetle, which is in line with its scientific species name - the 'sylvatica' bit of Cicindela sylvatica. The problem with this is that, in Britain at least, you find only them on heathlands and not in woods. So for this blog I've stuck with Heath Tiger Beetle.

I should also briefly mention Britain's other three tiger beetles, all of which I have yet to track down. All have even more restricted distributions than Heath Tiger Beetle, although Luff (2007) says that they can be 'occasionally abundant'. Two are from the same genus as Heath Tiger Beetle and look very similar. (Beetle experts will tell you that the distinction is that Heath Tiger Beetles have a black, not yellowish, labrum - the flat bit between the head and the jaws - but location and habitat are the easier initial pointers towards identification). Dune Tiger Beetle Cicendela maritima is (as its name suggests) found on coastal sand dunes, mostly in north Devon and south and central Wales. Cicindela hybrida (no common name) also lurks in dunes, but only in Lancashire and south Cumbria. Britain's final tiger beetle is Cylindera germanica (no common name, again), after having been booted out of the genus Cicindela by taxonomists. It has a similar colour to Green Tiger Beetle (metallic green) but is thinner with fewer spots. It's found on coastal grassy slopes in Dorset, Hampshire and the Isle of Wight, so it's one that I really need to check out. Watch this space.

References

Luff, Martin L (2008) Provisional atlas of the ground beetles (Coleoptera, Carabidae) of Britain. Biological Records Centre Institute of Terrestrial Ecology - link

Luff, Martin L (2007) The Carabidae (ground beetles) of Britain and Ireland. Royal Entomological Society Handbooks for the Identification of British Insects, vol 4(2) (2nd ed.)

Jones, Richard (2018) Beetles. (New Naturalist). London: HarperCollins

Websites

Species study - Back from the Brink

Species Recovery Trust Handbook